Shagay Ford, her son Ervens Jr. Ford, 17, her other son Jaylen Ford, 12, and her husband Ervens Ford, all from Miami, march on Monday, March 26, 2012, during the Trayvon Martin rally at Centennial Park in Sanford, Florida. Martin was killed was killed when a community watch volunteer thought he looked drugged out and suspicious. The volunteer called police and later wound up in a fight with him. (Chad Pilster of http://www.PilsterPhotography.com for the Miami Herald)

Trayvon Martin’s death galvanizes the nation for social justice.

Trayvon Martin’s case is creating a new social activism that hasn’t been seen for generations, as protesters demand an arrest of the shooter and the end to racial profiling. - 6:49 AM ET

In its zeal to champion property owners and the gun lobby, the state of Florida has created an outrageous legal loophole.

Protesters demonstrate at a rally for slain teenager Trayvon Martin on March 22, 2012, in Sanford, Florida. Sanford Police Department Chief Bill Lee announced this past week he would temporarily step down amid fierce pressure from those who say his department botched the handling of the case. - Mario Tama / Getty Images

All of us are debased by this. All of us — as Americans, as human beings — are simply worth less in this coarsened, brutish culture. Trayvon Martin was worth less, certainly — he was, by standards of the state of Florida, entirely expendable. And with these laws on the books, he will not be the last.

Now, for every case as unambiguous as this one — every case in which the gun-wielding assailant was, say, foolish enough to call police and provide evidentiary equivocations to dispatchers, or in which the victim left evidence of his own honest fears in a corroborated cell phone call to a girlfriend — there will be others in which someone simply walks up and shoots someone they dislike, or fear, or resent.

Now, by the grace of unthinking legislators and cynical governors, murderers can simply declare that they were in fear for their lives, or acting in self-defense, and, absent enough evidence to the contrary, investigators and prosecutors and jurors will be hard-pressed not to rule such thoughts and actions “reasonable” and therefore legal.

A quarter-century ago in Baltimore — a city contending with crime problems more profound than Sanford — a hard decision was made by law enforcement professionals serving a healthier, more courageous America. There and then, prosecutors looked at the case of a young man shot dead for the crime of theft, and they asserted for a society in which the taking of a human life is justifiable only in the most desperate extremity.

True, their suspect was an old man. True, he had been defending his property. And true , too, that prosecutors had no intention of seeing such a defendant incarcerated for his heedless use of lethal force, that they knew they would soon be negotiating with lawyers over a guilty plea and a term of probation for manslaughter. They didn’t want an old man in prison. But neither did they dare to send the wrong message, to suggest to all of us that there are acceptable reasons to kill, if indeed, you do not need to kill.

They charged the crime.

David Simon, a former police reporter with The Baltimore Sun, is the author of the non-fiction “Homicide: A Year On The Killing Streets,” an account of a year following the detectives of his city’s homicide unit. He is also the producer of HBO’s “The Wire” and “Treme.”